Looking for an explanation for my clear coat issue

[Bikerndiver]

So, here is what happened.....
I painted just the hood of my dune buggy. I did 3 coats of base and two coats of 2K clear. Then due to other things, I waited a month before paying anymore attention to the buggy.

Yesterday, I finally got back to work. Since so much time had elapsed, I went over the surface with a scotch brite pad, wiped it down and used a tack rag and then put a very light coat of the same clear used earlier. Just enough to give my next coat something to stick to.
This is when my incident occurred.
I waited about 8 minutes and I began to spray my clear and it instantly turned cloudy/milky..... This never happened to me before. Not being a professional, I read a lot about painting before I embarked on this journey to begin with. One of the things I read said if this happened I would just have to sand and start over..... UGH!!!!

So, since I had the clear ready to go, I decided to continue applying it. My logic being that if I needed to sand the whole thing anyway, what does a few more coats matter... I finished that coat, waited 20 minutes and applied a second coat, then waited 45 minutes and applied my third and final coat. There were some nice areas where the clear looked normal, but there were areas that looked cloudy too. I left to run some errands for a few hours.

With some dread, I went into my garage a few hours after my last clear coat and found a nice clear, shiny, glossy finish...no hint or trace of the cloudy/milkiness.

What the hell????? It was about 77 degrees in my garage and humidity was quite high...tropical even.
Two questions: First, why did it turn cloudy? Second, why did it clear up?
Thanks
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1966 Manx clone (possibly a Joe Poty Enterprises) named SANDY. '70 to '73 1300 cc w/1600 DP heads, twin carbs and headers

[Bobs67vwagen]

My recollection from working in a body shop many years ago is that high humidity can cloud the paint. Sometimes we would sand and polish it out, sometimes it has to be sprayed again. Why yours cleared up by itself my guess would be that the hardener overcame the effect of the humidity as the paint dried- just a guess though.

[Bikerndiver]

Your guess is better than my knowledge, I'm sure of that! Thank you for the response. I do have more painting to do, but I'm going to wait for the humidity to drop.
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1966 Manx clone (possibly a Joe Poty Enterprises) named SANDY. '70 to '73 1300 cc w/1600 DP heads, twin carbs and headers

[Bobs67vwagen]

Good idea, I bet you will have less problems. Good luck Bob

[jspbtown]

I am far from an expert but I agree.....humidity issue

[Bikerndiver]

@jspbtown. Thank you. In a way I'm glad it was the humidity and not my prep or application..... I'll wait till the weather changes and move on with the next step in my process.
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1966 Manx clone (possibly a Joe Poty Enterprises) named SANDY. '70 to '73 1300 cc w/1600 DP heads, twin carbs and headers

[jspbtown]

I also STRNGLY recommend using denatured alcohol as a final wipe down even if you used a degreaser.

Again....I am NOT a pro but I always found it worked very well in removing any contaminates.

[Bikerndiver]

@jspbtown The cleaner the better! Thank you!
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1966 Manx clone (possibly a Joe Poty Enterprises) named SANDY. '70 to '73 1300 cc w/1600 DP heads, twin carbs and headers

[Bobs67vwagen]

The shop I worked at used a product called final wash as the last step before painting. It might actually be alcohol, I never checked. 20 years ago I walked into an auto body supply store and bought some. It may still be available.

[jspbtown]

Again...from my VERY limited experience where I have had FAR more failures than successes...I find that lot of those final step washers/degreasers do not always evaporate completely leaving you with fisheyes, wrinkles, or other issues.

I Also think that a lot of newbies seem to think "the more the better" so they used a LOT of degreasers that can "hide" in cracks or pinholes. Alcohol always seems to evaporate quickly and completely

[Bobs67vwagen]

That sounds like a valid point to me as you certainly do not want residue of any kind on the surface to be painted.

[Bikerndiver]

Thanks everyone. I'm hoping to wrap this painting project up by the end of September. When I'm done, I'll post some pics.
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1966 Manx clone (possibly a Joe Poty Enterprises) named SANDY. '70 to '73 1300 cc w/1600 DP heads, twin carbs and headers

[oprn]

That right there is a classic high humidity problem! Yes sometimes it does clear up as it dries/cures and sometimes not.
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Our cars get old, we get old but driving an old VW never gets old!

[rg65]

My theory, humidity in the air was captured in the clear as it was applied. Once the clear had a time for solvents to escape it also took the water vapor with it. Kinda lucky must have a had really slow reducer that allowed the water to escape before the clear dried and trapped it. Had it stayed yellow it would have had to sand it back to the good clear. FYI there are some really good single stage paints on the market now that are easy to work with and pretty forgiving if repairs are needed. Seeing really good results with Eastwoods single stage products.

[raygreenwood]

By the way, do not use alcohol as a degreaser. Most alcohols are "co-solvent" with water and they actually absorbs moisture and entrains it on the surface for quite a while. Its why you use alcohol to dry moisture from your fuel system.

We use alcohol specifically for this in certain industrial processes.

If you have been getting away with it you have been lucky.

If you want to llok uo a simple automotive paint degreaser and check ingredients....look of Eastwoods PRE (or any other prep/degreaser).

It lists:
30-40% Naptha
30-40% Xylene
30-40% Toluene

Google any of those three and you find out none of them are Hygroscopic. They are all hydrophobic. They drive water away. That and they evaporate quick enough to carry away moisture when you have moving air on it but also evaporate slow enough so as not to "chill" thesurface which causes moisture to condense on the surface.

Ray